PAC Paranoia: Congress Faces Campaign Spending : Politics: Hysteria was the operative word when legislators realized they could not return home without tougher campaign finance laws.

Most senators have little to say publicly about the Keating case. But they are well aware of the potentially damaging impact on the senators under investigation. Like Durenberger, none of the five face reelection this November and they are attempting to carry on with business as usual.

A mood of hysteria also has increasingly surrounded the onset of this November's election. Many lawmakers, Democrats and Republicans, have been edgy lately as they prepare for a fall campaign in which "incumbent" may be a nine-letter political synonym for "scum."

Politicians have abundant financial problems to answer for in this fall's campaign: the catastrophic S&L mess; the federal deficit and, lest we forget, the 25% pay raise that House members voted themselves last fall after rejecting a 50% boost.

In each case, members of Congress understand that they have been part of an institutional failure to respond to real problems. In the past, most of them have been able to keep their distance, as individuals, from these hot wires. The difference in 1990 may be that voters are demanding accountability and seeking culprits.

Pollsters from both parties have found a drop of roughly 10%, when they ask voters whether they are inclined to reelect incumbents. Most lawmakers will survive this year if only because few face opponents who are even semi-credible or have adequate financing. But both parties are gearing up for surprise election setbacks.

This atmosphere helps to explain why one of the most popular political activities these days is the lineup of nervous incumbents, in a modern-day act of expatiation, returning their contributions from savings-and-loan executives. Whether their new-found purity removes their earlier sins will be up to the voters.